POS1510 IDENTIFICATION OF THE MINIMAL REQUIRED DURATION OF RENAL-EXTRARENAL REMISSION ASSOCIATED WITH REDUCED RISK OF CHRONIC KIDNEY DISEASE AND OF DAMAGE ACCRUAL IN LUPUS NEPHRITIS
Authors: M. Gatto, G. Frontini, M. Calatroni, F. Reggiani, B. Trezzi, S. Quaglini, R. A. Sinico, L. Iaccarino, G. Moroni, A. Doria
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> There is an increasing need for data exploring the effect of remission on kidney-oriented outcomes and terminal organ damage in patients with lupus nephritis (LN). <h3>Objectives</h3> To investigate the effects of renal-extrarenal clinical remission on chronic kidney disease (CKD) development and organ damage accrual in patients with LN. <h3>Methods</h3> We performed a multicentric retrospective cohort study on biopsy-proven LN patients with at least five years follow-up, in whom we assessed i) the minimum duration of remission able to prevent CKD (serum creatinine &gt;1.0mg/dl with eGFR &lt;60ml/min/1.73 m2 and inactive urinary sediment, confirmed by at least three determinations for at least 3 months); ii) the impact of remission on organ damage increase, evaluated by the SLICC Damage Index (SDI). Renal-extrarenal clinical remission was defined as serum creatinine &lt;1mg/dl, eGFR&gt;60 ml/min/1.73m2, proteinuria &lt;0.5g/24h and cSLEDAI=0, lasting for at least one year. Cox regression was used to test the effect of different durations of remission on CKD and SDI accrual. The minimum duration of remission needed to prevent CKD was estimated through Kaplan-Meier curves. The potential relationship between renal-extrarenal clinical remission and SDI was assessed by Spearman correlation between percentage of follow-up spent in remission and annual increase in SDI. <h3>Results</h3> 303 LN patients were included (females 86.5%, mean follow-up 14.8 (9.8-22.0) years). 84.8% achieved renal-extrarenal clinical remission that persisted for 8.70 (5.40-13.30) years. Overall, 17.6% patients developed CKD after a median of 14.1 (8.9-20.9) years. Patients achieving remission developed CKD significantly less frequently than patients never achieving remission (12.1% vs. 56.6%, p&lt;0.001). Among patients with at least 10-year follow-up (n=224), a remission duration of at least 2 years protected from CKD development (p&lt;0.001), yet the best CKD-free survival was obtained in patients reaching at least 3 years of remission (HR95%CI 2.34 (1.38-3.98) p&lt;0.001) (<b>Figure 1</b>). Considering the whole population, the increase in SDI from baseline to the last observation was significantly higher in patients who had never achieved remission (median: 2[1-3] vs. 1[0-1]; p= 0.047). We observed that the higher the percentage of follow-up spent in remission, the lower the yearly SDI accrual (r=-0.324, p&lt;0.001). Among patients achieving remission, the risk of any SDI increase was significantly lower in patients maintaining at least 3 years on remission vs. shorter durations (HR95% CI 0.54 (0.31-0.54), p=0.03). <h3>Conclusion</h3> Renal-extrarenal clinical remission is an achievable treatment target which protects against CKD development and SDI increase in patients with LN. At least 3 years of renal-extrarenal clinical remission confers significant protection against renal function deterioration and chronic damage, hence emerging as a desirable therapeutic target for LN. <h3>REFERENCES:</h3> NIL. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> Mariele Gatto Speakers bureau: GSK, Giulia Frontini: None declared, Marta Calatroni: None declared, Francesco Reggiani: None declared, Barbara Trezzi: None declared, Silvana Quaglini: None declared, Renato Alberto Sinico: None declared, Luca Iaccarino Speakers bureau: GSK, Gabriella Moroni Speakers bureau: GSK, Andrea Doria Speakers bureau: GSK, Pfizer, AZ, Celgene, Eli-Lilly, BMS, Roche.